391 / 2022-03-15 19:14:38

Partial Discharge Characteristics of Electrical Tree in XLPE during DC and Voltage Drop

DC voltage,partial discharge,Electrical trees

Purpose/Aim

The electrical tree defect is the typical defect in XLPE insulation, causing gradual degradation of insulation performance. The typical pattern of electrical tree defects under AC voltage is well known, while the electrical tree defect under DC voltage is rarely mentioned. This paper focuses on the partial discharge characteristics of electrical tree defects under DC voltage and provides a reference for the research of DC high-voltage (HV) cable transmission.

Experimental/Modeling methods

The XLPE samples with a needle-plate structure were used in this experiment, and the partial discharge (PD) was detected by the pulse current method. The tree growth and partial discharge under DC voltage and the voltage drop were measured. The statistical parameters under different DC voltages were studied.

Results/discussion

In the study, the initiated tree does not grow at 25 °C, 30 kV. When the temperature increased to 50 °C, the rapid growth of the electrical tree was observed. Meanwhile, the PD amplitude and frequency increase. Notably, the PD was detected during the decay of the applied voltage, which may be related to the existing space charge in the electrical tree.

Conclusions

The rise of temperature promotes the growth of the electrical tree and the amplitude and frequency of PD under DC voltage. When the high DC voltage applied to the insulating sample gradually drops to zero, the electrical tree defects generate PD.